1. Field of the Invention
The present invention relates generally to wheelchairs and, more specifically, to wheelchairs employing mechanisms that increase the mechanical advantage to reduce the effort of propelling the vehicle while conversely providing the means of increasing that effort to allow the operator to use the wheelchair as an exercise machine for maintaining physical fitness. The present invention, the Easy Glide Chair Kit, provides a wheelchair so equipped: with two separate hand-operated brakes for each wheel, two tensioning bolts for varying the operating resistance of each main wheel, two extendable legs for immobilizing the chair for exercise operation only and two hand-operated drive mechanisms for each main wheel which allow the operator to propel the chair forward or backward, stop and turn, using differential input.
The drive mechanism consists of a hand-operated, generally vertically-oriented lever connected to a reversible ratchet assembly that in turn drives a speed-reducing gear assembly consisting of a smaller ratchet-driven ratchet/gear cluster driving the larger gear which is rigidly mounted to and axially aligned with each main wheel. Additionally, adjustable resistive means are provided for each side for increasing or decreasing the force required to operate the handle to provide the operator with means for selectively exercising the upper muscular and cardiovascular systems. Another health related feature of the present invention is its ability to convert a wheelchair to use purely as an exercise machine, by providing a pair of extendable legs or jacks mounted on either side at the rear portion of the chair for lifting the main wheels off the ground, thereby allowing them to rotate freely. In all, the present invention provides a more comprehensive solution, compared to prior art, to the mobility and immobility health related problems of wheelchair bound persons.
2. Description of the Prior Art
There are other hand operated drive systems designed for wheelchairs. Typical of these is U.S. Pat. No. 4,460,190 issued to Spiess on Jul. 17, 1984.
Another patent was issued to Herron on Dec. 24, 1985 as U.S. Pat. No. 4,560,181. Yet another U.S. Pat. No. 4,758,013 was issued to Agrillo on Jul. 19, 1988 and still yet another was issued on Apr. 28, 1998 to Weaver as U.S. Pat. No. 5,743,544.
A three wheeled wheelchair wherein two of the wheels are leading wheels with the single wheel being a trailing wheel. The wheelchair is propelled through the use of a chain drive assembly which is to be manually operated through the use of a handle assembly. Adjacent the handle assembly is a seat which is to support the occupant of the wheelchair. The seat is cushionly supported by a shock absorber assembly. The handle assembly is attached to a steering mechanism which, through lateral movement of the handle assembly, causes the leading wheels to be turned in respect to the frame of the wheelchair. A separate turning wheel assembly is to be manually movable to an extended position to cause the trailing wheel to be spaced from the supportive surface thereby permitting three hundred and sixty degree turning of the wheelchair about a single point.
A wheelchair and drive mechanism powered by reciprocating operation of a drive lever. The drive mechanism provides a continuously variable gear ratio allowing wheelchair operation at varying speeds and on differing inclines; and is readily fitted to a standard wheelchair by a drive-associated bayonet mount. A drive mechanism ratchet wheel includes an upper and lower radial crank secured for rotation thereabout by an axle. Each crank includes a pawl assembly that engages with circumferential ratchet wheel teeth to transfer drive energy supplied to the radial cranks from connecting arms to the ratchet wheel. The connecting arms are coupled to a reciprocating lever arm and operate in concert with the pawls to alternately engage with and transfer energy to the ratchet wheel, or disengage therefrom. While one connecting arm and associated pawl is transferring energy to the ratchet wheel, the other connecting arm is disengaging an associated pawl from the ratchet wheel. Energy is transferred during both a forward and rearward stroke of the lever arm to effect efficient wheelchair and drive operation.
A hand crank powered wheelchair with forward, coast, reverse, and braking capability. The wheelchair has a left and right hand crank. Each hand crank is used to independently control the two rear wheels. A clutch and brake is contained in the hub of each rear wheel. The clutch drives wheel forward when hand crank is rotated forward and allows wheel to coast when hand crank stops rotation. A reverse enable lever selects brake or reverse mode. When in brake mode minimal energy applied to crank in the reverse direction will slow or stop rear wheel. When in reverse mode, brake acts as clutch, allowing reverse rotation of hand crank to drive rear wheel backward. The drive may include a gear shift mechanism. Drives of the invention may be applied to other wheeled vehicles such as delivery tricycles.
An improved wheelchair and hub assembly is described that interposes reduction gearing between the handring or rotatable hand wheel and the drive wheel of the assembly. This gearing provides some mechanical advantage to users who may lack sufficient strength to propel themselves in a conventional wheelchair, especially in a home environment. A single speed assembly is described which is operated conventionally by rotating handrings either forward or rearward to produce a corresponding rotation of the drive wheel but, unlike conventional wheels, a complete revolution of the handring results in only a partial revolution of the drive wheel. In the hub of the assembly is a wheel locking mechanism which enables the wheel to be easily and positively locked for the safety of the user, preventing rotation of the wheel in either direction. Additionally, a ratcheting mechanism is incorporated into the hub design which can be engaged to allow forward rotation but prevent rearward rotation of the drive wheels.
While these wheelchair hand operated drive systems may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention, as hereinafter described.
A primary object of the present invention is to provide a universal conversion kit for a wheelchair with independent, hand-powered, lever-operated, speed reducing, drive mechanisms for each wheel whereby the operator thereof may be able to easily propel the wheelchair forward, backward, as well as turn using differential input.
Another object of the present invention is to provide a universal wheelchair conversion kit with independent, hand-powered, speed reducing, drive mechanisms for each wheel that also provides independently operating hand brakes for safety and maneuverability.
Another object of the present invention is to provide a universal wheelchair conversion kit with independent, hand-powered, speed reducing, drive mechanisms for each wheel, independent hand brakes, and means for varying the input drive effort to allow the operator to use the wheelchair as a mobile exercise machine to improve and maintain upper body muscular and cardiovascular systems.
A still further object of the present invention is to provide a universal wheelchair conversion kit with independent, hand-powered, speed reducing, drive mechanisms for each wheel, with independent hand brakes, means for operating as a mobile exercise machine, having further means for converting the mobile exercising capability to a stationary configuration.
Additional objects of the present invention will appear as the description proceeds.
The present invention overcomes the shortcomings of the prior art by providing an economical, universal wheelchair conversion kit which offers two, hand-powered, variable-resistive, drive mechanisms for the main wheels of a wheelchair which can be retrofitted to existing wheelchairs and that provide the operator of the vehicle means of easy mobility, independent brakes for safety and maneuverability, and the resistive means for exercising the upper body musculature and the cardiovascular systems while using the chair in either a mobile or stationary configuration. In all, the present invention provides a more comprehensive solution, compared to prior art, to the mobility and immobility health related problems of wheelchair bound persons.
The foregoing and other objects and advantages will appear from the description to follow. In the description reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. In the accompanying drawings, like reference characters designate the same or similar parts throughout the several views.
The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.